Tire pressure warning device



Dec. 3, 1940. E. L. LUNDE TIRE PRESSURE WARNING DEVICE Filed June 25, 1938 /zg 'f I BY any' A TTGRNE Y Patented Dec. 3, 1940 UNITED STATES PATENT OFFICE TIRE PRESSURE WARNING DEVICE Edwin L. Lunde, .Sioux City, Iowa` Application June 25, 1938, Serial No. 215,761

4 Claims. (Cl. 200--58) My device relates to signalling arrangement enter into the invention. The dual casings are usable with pneumatic tires. indicated by the characters I2 and the inner tubes An object of my invention is to provide a warnby the character I3. Suitable discs or spokes I4 ing signal to ash when a tire is deflated beyond are shown in the usual manner which are con- 5 a certain limit. nected to the axle housing. The rim I5 includes 5 A further object of my invention is to provide an opening I5 through which passes the stem I'I. such an arrangement especially usable with dual The stem I'I is attached at I8 to the rubber memtires. ber I9 which bears against the inner tube I3. A further object of my invention is to provide The stem II includes the threaded portion 2D 10 adjustable means associated with the device so upon which is screwed the nut 2l. A housing 10 that the device can be varied for desired pressures. member 22 is threadably engaged with the fur- A further object of my invention is to provide ther coupling member 23, which coupling is ata device of such character which does not necestached to the iixed member 23a which is attached sarily involve constantly contacting mechanical to the rim I5. Threadably engaged with the parts but only maintains contact when a lower member 22 and at the top thereof is the cap 24. 15 pressure is reached. A lengthened rod 25 passes through an opening A further object of my invention is to provide 26 in the side of the member 22 and includes the an arrangement which can be adapted to standend portion 2l through which passes a continuaard vehicles such as heavy trucks and the like tion of the stem 2i). Received between the cap 24 and which can be manufactured at a reasonable and the member 21 is the comparatively strong 20 cost. compression spring 28 which is maintained under With these and other objects in view, my inpressure, It will be noted that the spring 28 revention consists in the construction, arrangement ceives the upper end of the stem 2U. Enclcsing and combination of the various parts of my dethe rod is the pipe housing 29 which is at- 25 vice, whereby the objects contemplated are atcached to the member 22 by means of the coupling 25 tained, as hereinafter more fully set forth, pointed 30. The rod 25 extends into the downwardly bent out in my claims, and illustrated in the accomportion 3l which again terminates in the forward panying drawing, in which: horizontal portion 32 upon which is rotatably Figure 1 is a sectional view taken substantially j ournalled the small roller 33. through the axle of a dual tire arrangement, The stationary disc portion of the vehicle which 30 Figure 2 is a diagram showing the electrical is attached rigidly thereto and which does not structure, rotate is indicated by the character 34. A metal Figure 3-is a further detail, and circular band 35 is attached to an insulating strip Figure 4 is an enlarged detail of the contact- 36 which is attached to the portion 34. A further 35 ing arrangement. cylindrical band 3l is` also attached to the portion 35 The principal difficulty encountered in dual tire 34. It will be noted that there are two such ararrangements is that when one of the tires berangements as shown in Figure l, one of which comes low through loss of air pressure injury is passes to the outer casing and one of which passes caused to the casing etc. through frictional rubto the inner casing, which in the latter respect bing and the like since the tire is correspondingly is located oppositely to the lower and which in- 40 freer to move upon the rim and as` a result such Volves the use of a shorter pipe housing 29, Atobjectionable features are encountered. It is nectached at 38 to the upper and lower pipe housings essary for the driver to frequently get out of the is the arcuate shield 39 which serves to shield the car and to apply pressure against the casing to mechanism therein against the entrance of dirt see if the tire is low. etc. and the ring member 36 also serves the same 45 The principal object of my invention is to elimifunction so that as a result the entire arrangenate such objectionable practices and to provide ment is enclosed against adverse conditions such an automatic feature which Will indicate readily as Weather etc. whether the tire pressure has dropped to the The electrical connections are shown in Figure danger point. 2 wherein the character 40 shows the battery 50 I have used the character IIJ to designate genwhich is grounded at 4I and it will be noted that erally the axle housing which receives the usual there are two electric bulbs, a left hand bulb 42 axle With the character II indicating the housand a right hand bulb 43 for indicating correing containing the brake bands etc, which need sponding deflations of the tire.

not be elaborated on herein since they do not The contact rings 35 are shown in the circuit 55 with the upper, for instance, representing the left hand side and the lower, the right hand side. The contact rod 32, of course, is grounded at 44 since all of the contacts are grounded through the mechanical arrangement. It will be noted that during normal operation and normal pressure conditions that the contact roller 33 will be maintained at a slight distance from the contact ring 35 since the pressure is forced against the spring 28. However, as soon as the pressure drops in the tube I3, the spring 28 will force the rod 25 downwardly thereby carrying the roller 33 against the ring 35 and establishing the contact tothe grounded side which in turn causes the light 42 or 43 to glow indicating to the driver that the corresponding side is deilated.

The nut 2| allows permanent adjustment for any pressure since the same can be screwed upon the stem upwardly or downwardly to indicate corresponding pressures which automatically adjusts the spring for this purpose. This can be accomplished by unscrewing the member 22 from the coupling 23 and by use of a suitable tool or small rod the nut 2| can be adjusted. However, temporary adjustments can be made by means of the nut 24 which can be turned either to the left or right to adjust the tension of the spring 28, thereby effecting the necessary adjustment to the rod 25. The threads on the screw cap 24 can be made close tting to maintain a tight and secure t, and the spring 28 will also act as a lock t0 prevent the nut from turning. It will be particularly noted in my invention that there are no contact parts unless such is necessary, in other words, the entire arrangement is carried as a rigid structure while the Wheel is turning and the contact is not established until the dangerous point is reached in deilation. It will also be noted that any of the parts can be removed easily when it is necessary to change the tires or the rim and it will be further noted from my invention that the parts are simple, will not get out of order, are weather and dust resisting etc., and involve a minimum of parts.

Some changes may be made in the construction and arrangement of the parts of my invention without departing from the real spirit and purpose of my invention, and it is my intention to cover by my claims any modified forms of structure or use of mechanical equivalents, which may be reasonably included within their scope.

I claim as my invention:

l. A tire pressure warning device comprising a stem received through a tire rim, a spring normally urging said stem outwardly against the tire pressure, means attachable to said stern to complete anv electric circuit to indicate pressure drop in said tire, said means including an extended rod, a contact ring carried by the stationary portion of a vehicle and normally spaced from the termination of said rod, a contact roller rotatably journalled at the end of the rod, said contact ring being insulated from said portion, means for adjusting the indicating pressure including a nut threadedly engaged with said stem,

said nut adapted to abut against said extended rod for adjusting tension against said spring.

2. A tire pressure warning device comprising a stem received through a tire rim, a spring normally urging said stem outwardly against the tire pressure, means attachable to said stem to complete an electric circuit to indicate pressure drop in said tire, said means including an extended rod, a contact ring carried by the stationary portion of a vehicle and normally spaced from the termination of said rod, a contact roller rotatably journalled at the end of the rod, said contact ring being insulated from said portion, means for adjusting the indicating pressure including a nut threadedly engaged with said stem,

said nut adapted to abut against said extended rod for adjusting tension against said spring, a tubular housing including said stem, a further tubular protecting member attached to said housing for covering said extended rod.

3. A tire pressure Warning device comprising a stem received througha tire rim, a spring normally urging said stem outwardly against the tire pressure, means attachable to said stem to complete an electric circuit to indicate pressure dropA in said tire, said means including an extended rod, a contact ring carried by the stationary portion of a vehicle .and normally spaced from the termination of said rod, a contact roller rotatably journalled at the end of the rod, said contact ring being insulated from said portion, means for adjusting the indicating pressure including a nut threadedly engaged with said stem, said nut adapted to abut against said extended rod for adjusting tension against said spring, a tubular housing including said stem, a further tubular protecting member attached to said housing for covering'said extended rod, said warning device` attached in opposed relation to alternate tires of a dual tire arrangement.

4. A tire pressure warning device comprising a stem received through a tire rim, a spring normally urging said stem outwardly against the tire pressure, means attachable to said stem to complete an electric circuit to indicate pressure drop in said tire, said means including an extended rod, a contact ring carried by the stationary portion of a Vehicle and normally spaced from the termination of said rod, a contact roller rotatably journalled at the end of the rod, said contact ring being insulated from said portion, means for adjusting the indicating pressure vincluding a nut threadedly engaged with said stein, said nut adapted to abut against said extended rod for adjusting tension against said spring, a tubular housing including said stem, a further tubular protecting member attached to said housing for covering said extended rod, said warning device attached in opposed relation to alternate tires of a dual tire arrangement, a protecting housing attached toV said tubular rod inclosing members, said housing adapted to cover and inclose all said contacting arrangements.

EDWIN L. LUNDE. 

